Organic carbon partitioning during spring phytoplankton blooms in the Ross Sea polynya and the Sargasso Sea

Limnology and Oceanography - Tập 43 Số 3 - Trang 375-386 - 1998
Craig A. Carlson1, Hugh W. Ducklow2, Dennis A. Hansell3, Walker O Smith4
1Bermuda Biological Station for Research, Ferry Reach, St. George's GEOl, Bermuda
2The College of William and Mary, Virginia Institute of Marine Science, P.O. Box 1346, Gloucester Point, Virginia 23062-1346
3Bermuda Biological Station for Research
4Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, 37996

Tóm tắt

In this study we evaluate the partitioning of organic carbon between the particulate and dissolved pools during spring phytoplankton blooms in the Ross Sea, Antarctica, and the Sargasso Sea. As part of a multidisciplinary project in the Ross Sea polynya we investigated the dynamics of the dissolved organic carbon (DOC) pool and the role it played in the carbon cycle during the 1994 spring phytoplankton bloom. Phytoplankton biomass during the bloom was dominated by an Antarctic Phaeocystis sp. We determined primary productivity (PP; via H14CO3, incubations), particulate organic carbon (POC), bacterial productivity (BP; via [3H]thymidine incorporation), and DOC during two occupations of 76°30′S from 175°W to 168°E. Results from this bloom are compared to blooms observed in the Sargasso Sea in the vicinity of the Bermuda Atlantic Time‐Series Study station (BATS). We present data that demonstrate clear differences in the production, biolability, and accumulation of DOC between the two ocean regions. Despite four‐ to fivefold greater PP in the Ross Sea, almost an order of magnitude less DOC (mmol m−2) accumulated during the Ross Sea bloom compared to the Sargasso Sea blooms. In the Ross Sea 89% (˜1 mol C m−2) of the total organic carbon (TOC) that accumulated during the bloom was partitioned as POC, with the remaining 11% (˜0.1 mol C m−2) partitioned as DOC. In contrast, a mean of 86% (0.7.5–1.0 mol m−2) of TOC accumulated as DOC during the 1992, 1993, and 1995 blooms in the Sargasso Sea, with as little as 14% (0.08–0.29 mol C m−2) accumulating as POC. Although a relatively small portion of the fixed carbon was produced as DOC in the Ross Sea, the bacterial carbon demand indicated that a qualitatively more labile carbon was produced in the Ross Sea compared to the Sargasso Sea. There are fundamental differences in organic carbon partitioning between the two systems that may be controlled by plankton community structure and food‐web dynamics.

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Limnology and Oceanography

Tập 43 Số 3

375-386

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